1. Field of the Invention
This invention relates to a colorimetry converting apparatus.
2. Description of the Prior Art
A colorimetry converting apparatus for converting a single video signal having a colorimetry to another single video signal having different colorimetry is known.
There are various types of video signals having different formats which are compressed by different compression methods. For example, the motion picture video signal is compressed in accordance with MPEG (Motion Picture Expert Group) 2 and the still picture signal is compressed in accordance with JPEG (Joint Photographic Coding Experts Group). Moreover, characters are represented by characters codes and figures are expressed by the PNG (portable Network Graphics) format.
Both the MPEG 2 and JPEG use Y (luminance), Cr and Cb (Color difference signals) as original data. On the other hand, graphics data like PNG uses RGB as original data. However using the same Y, Cr, Cb as original data, the transfer matrix from YCrCb to RGB (or vice versa) is different among various compression or graphic formats.
For the monitors, RGB and YCrCb are both used. So when the monitor has YCrCb inputs, RGB signal should be again transferred to YCrCb signal according to the colorimetry of the monitor.
Moreover, conversion methods of satellite broadcast video signals are different from one country to another country.
On the other hand, in U.S.A. 1080I format (which is interlace scan and the effective lines are 1080) and 720P format (which is progressive scan and the effective lines are 720) have the colorimetry of BT 709, while 480I format (which is interlace scan and the effective lines are 480) and 480P format (which is progressive scan and the effective lines are 480) have the colorimetry of BT601.
Moreover, in the case of the monitor, both in U.S.A. and Japan, the video signals according to 1080I and 720P format should be inputted using the colorimetry BT709, while the video signals according to 480I and 480P format should be inputted using the colorimetry BT601.
Moreover, the colorimetry most frequently used in JPEG data is SMPTE (Society of Motion Picture and Television Engineers) 240M.
The following equations Eq. 1, Eq. 2, and Eq. 3 are conversion equations for converting RGB video signals according to BT601, BT709, and SMPTE 240M to YCrCb video signals, respectively. The following equations Eq. 4, Eq. 5, and Eq. 6 are conversion equations for converting YCrCb video signals according to BT601, BT709, and SMPTE 240M to RGB video signals, respectively.                               "LeftBracketingBar"                                                    Ey                                                                    Ecr                                                                    Ecb                                              "RightBracketingBar"                =                              "LeftBracketingBar"                                                                                0                    ⁢                                          xe2x80x83                                        ⁢                    .299                                                                    0.587                                                                      0.                    ⁢                                          xe2x80x83                                        ⁢                    114                                                                                                                    0                    ⁢                                          xe2x80x83                                        ⁢                    .5                                                                                        -                    0.419                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    081                                                                                                                                          -                      0                                        ⁢                                          xe2x80x83                                        ⁢                    .169                                                                                        -                    0.331                                                                                        0.                    ⁢                                          xe2x80x83                                        ⁢                    5                                                                        "RightBracketingBar"                    ⁢                      "LeftBracketingBar"                                                            Er                                                                              Eg                                                                              Eb                                                      "RightBracketingBar"                                              (                  EQ          .                      xe2x80x83                    ⁢          1                )                                          "LeftBracketingBar"                                                    Ey                                                                    Ecr                                                                    Ecb                                              "RightBracketingBar"                =                              "LeftBracketingBar"                                                                                0                    ⁢                                          xe2x80x83                                        ⁢                    .2126                                                                                        0.                    ⁢                                          xe2x80x83                                        ⁢                    7152                                                                                        0.                    ⁢                                          xe2x80x83                                        ⁢                    0722                                                                                                                    0                    ⁢                                          xe2x80x83                                        ⁢                    .5                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    454                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    046                                                                                                                                          -                      0                                        ⁢                                          xe2x80x83                                        ⁢                    .115                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    385                                                                                        0.                    ⁢                                          xe2x80x83                                        ⁢                    5                                                                        "RightBracketingBar"                    ⁢                      "LeftBracketingBar"                                                            Er                                                                              Eg                                                                              Eb                                                      "RightBracketingBar"                                              (                  EQ          .                      xe2x80x83                    ⁢          2                )                                          "LeftBracketingBar"                                                    Ey                                                                    Ecr                                                                    Ecb                                              "RightBracketingBar"                =                              "LeftBracketingBar"                                                                                0                    ⁢                                          xe2x80x83                                        ⁢                    .212                                                                                        0.                    ⁢                                          xe2x80x83                                        ⁢                    701                                                                                        0.                    ⁢                                          xe2x80x83                                        ⁢                    087                                                                                                                    0                    ⁢                                          xe2x80x83                                        ⁢                    .5                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    445                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    055                                                                                                                                          -                      0                                        ⁢                                          xe2x80x83                                        ⁢                    .116                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    384                                                                                        0.                    ⁢                                          xe2x80x83                                        ⁢                    5                                                                        "RightBracketingBar"                    ⁢                      "LeftBracketingBar"                                                            Er                                                                              Eg                                                                              Eb                                                      "RightBracketingBar"                                              (                  EQ          .                      xe2x80x83                    ⁢          3                )                                          "LeftBracketingBar"                                                    Er                                                                    Eg                                                                    Eb                                              "RightBracketingBar"                =                              "LeftBracketingBar"                                                                                1                    ⁢                    .0                                                                                        1.                    ⁢                                          xe2x80x83                                        ⁢                    4016867602                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    0009267448                                                                                                1.0                                                                                            -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    7141690400                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    3436953845                                                                                                1.0                                                                      0.                    ⁢                                          xe2x80x83                                        ⁢                    0009902205                                                                                        1.                    ⁢                                          xe2x80x83                                        ⁢                    7721604157                                                                        "RightBracketingBar"                    ⁢                      "LeftBracketingBar"                                                            Ey                                                                              Ecr                                                                              Ecb                                                      "RightBracketingBar"                                              (                  EQ          .                      xe2x80x83                    ⁢          4                )                                          "LeftBracketingBar"                                                    Er                                                                    Eg                                                                    Eb                                              "RightBracketingBar"                =                              "LeftBracketingBar"                                                                                1                    ⁢                    .0                                                                                        1.                    ⁢                                          xe2x80x83                                        ⁢                    5749131625                                                                                        0.                    ⁢                                          xe2x80x83                                        ⁢                    0004920110                                                                                                1.0                                                                                            -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    4683216869                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    1874855952                                                                                                1.0                                                                      0.                    ⁢                                          xe2x80x83                                        ⁢                    0016223285                                                                                        1.                    ⁢                                          xe2x80x83                                        ⁢                    8557492542                                                                        "RightBracketingBar"                    ⁢                      "LeftBracketingBar"                                                            Ey                                                                              Ecr                                                                              Ecb                                                      "RightBracketingBar"                                              (                  EQ          .                      xe2x80x83                    ⁢          5                )                                          "LeftBracketingBar"                                                    Er                                                                    Eg                                                                    Eb                                              "RightBracketingBar"                =                              "LeftBracketingBar"                                                                                1                    ⁢                    .0                                                                                        1.                    ⁢                                          xe2x80x83                                        ⁢                    5758476316                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    0006567605                                                                                                1.0                                                                                            -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    4765290206                                                                                                              -                      0.                                        ⁢                                          xe2x80x83                                        ⁢                    2264181923                                                                                                1.0                                                                      0.                    ⁢                                          xe2x80x83                                        ⁢                    0003776373                                                                                        1.                    ⁢                                          xe2x80x83                                        ⁢                    8259584599                                                                        "RightBracketingBar"                    ⁢                      "LeftBracketingBar"                                                            Ey                                                                              Ecr                                                                              Ecb                                                      "RightBracketingBar"                                              (                  EQ          .                      xe2x80x83                    ⁢          6                )            
In Eqs. 1 to 6, each Ey is an analog value from zero to one, each Ecr and each Ecb are analog values from xe2x88x920.5 to 0.5 and each Er, each Eg, and each Eb are analog values from zero to one.
Moreover, values of digital values of Y, Cr, and Cb actually used in MPEG method are calculated in accordance with the following equation.
Y=219xc3x97Ey+16
Cr=224xc3x97Ecr+128
Cb=224xc3x97Ecb+128xe2x80x83xe2x80x83(EQ. 7)
As mentioned, the conversion equations, that is, colorimetries are different each other among the compression methods or standards (formats) of video signals. The prior art colorimetry conversion apparatus converts one type of video signal having one colorimetry to another video signal having another colorimetry independently.
The aim of the present invention is to provide a superior colorimetry converting apparatus.
According to this invention, there is provided a first colorimetry converting apparatus including: an input circuit for receiving a plurality of input video signals respectively having different first colorimetries; and a colorimetry converting circuit for converting the input video signals to a single output video signal having a second colorimetry.
In the first colorimetry converting apparatus, the different types of input video signals may be inputted to the input circuit in parallel.
In the first colorimetry converting apparatus, the different types of input video signals may be successively inputted to the input circuit.
In the first colorimetry converting apparatus, the outputting circuit may time-divisionally output the second video signals within a frame of the single output video signal.
The first colorimetry converting apparatus may further include an area signal generation circuit for generating an area signal indicative of a partial area of a frame of the single output video signal. The colorimetry converting circuit converts one of the input video signals to the single output video signal at the partial area and converts another one of the input video signals at outside of the partial area in accordance with the area signal.
Each of the input video signals in the first colorimetry converting apparatus may include a luminance signal and color difference signals and the colorimetry converting circuit includes, as a second colorimetry converting apparatus, a first switch for outputting a part of the input video signals, a first converting circuit converting the part of input video signals from the first switch to RGB-color signals in accordance with the colorimetries of the part of input video signals from the first switch respectively, a second switch for outputting one of the RGB-color signals, and a second converting circuit for converting the RGB-color signal to the single video signal including a luminance signal and color difference signals.
The first colorimetry converting apparatus may further include, as a third colorimetry converting apparatus, another input circuit for receiving an input RGB-color signal. Each of the input video signals includes a luminance signal and color difference signals. The colorimetry converting circuit includes a first switch for outputting a part of the input video signals, a first converting circuit respectively converting the part of input video signals from the first switch to RGB-color signals in accordance with the colorimetries of the part of input video signals from the first switch respectively, a second switch for outputting one of the RGB-color signals and the input RGB-color as a converted RGB-color signal, and a second converting circuit for converting the converted RGB-color signal to the single output video signal including a luminance-signal and color difference signals to have the second colorimetry.
The second colorimetry converting apparatus may further include, as a fourth colorimetry converting apparatus, an area signal generation circuit for generating an area signal indicative of at least a partial area of a frame of the single output video signal, a switching signal generation circuit for generating first to third switching signals respectively supplied to the first switch, the first converting circuit, and the second switch such that one of the input video signals is converted into the single video signal at the partial area and another one of the input video signals is converted at outside of the partial area in accordance with the area signal.
The second colorimetry converting apparatus may further include, as fifth colorimetry converting apparatus, a switching signal generation circuit for generating first to third switching signals respectively supplied to the first switch, the first converting circuit, and the second switch in response to a vertical synchronizing signal.
In the third colorimetry converting apparatus, the switching signal generation circuit may further generate fourth switching signal supplied to the second converting circuit which converts the RGB-color signal to the single output video signal in response to the vertical synchronizing signal.
The fourth colorimetry converting apparatus may further include an operation switch for generating a setting signal. The second converting circuit converts the RGB-color signal to the single output video signal in accordance with the setting signal.
In the first colorimetry converting apparatus, colorimetries of the input video signals change respectively according to the time.
In the first colorimetry converting apparatus, a colorimetry of output signal can change according to the time.
In the first colorimetry converting apparatus may further include an area signal generation circuit for generating area signals indicative of partial areas of a frame of the output video signal. The partial area corresponds to each the input video signal, the colorimetry converting circuit converts colorimetry of each input video signal according to the corresponding area signal.
In the first colorimetry converting apparatus may further include an additional input circuit for RGB-color signals. The converting circuit includes a first switch for outputting a part of the luminance and color difference input video signals, a first converting circuit respectively converting the part of input video signals from the first switch to RGB-color signals in accordance with the colorimetry of the part of input video signals from the first switch respectively, a second switch for outputting an selected RGB-color signal among one of the RGB-color signals from the first converting circuit and the additional input circuit, and a second converting circuit for converting the RGB-color signal to the single video output signal of luminance and color difference to have the further different colorimetry.
In the second colorimetry converting apparatus may further include an area signal generation circuit for generating area signals indicative of an area in a frame of the single output video signal, a switching signal generation circuit for generating switching signals corresponding to each of input video signals respectively supplied to the first switch, the first converting circuit, and the second switch such that each of the input video signals is converted into the single video signal according to its corresponding area signal.
The third colorimetry converting apparatus may further include an area signal generation circuit for generating area signals indicative of an area in a frame of the single output video signal, a switching signal generation circuit for generating switching signals corresponding to each of input video signals respectively supplied to the first switch, the first converting circuit, and the second switch such that each of the input video signals is converted into the single video signal according to its corresponding area signal.
In the second colorimetry converting apparatus may further include, as a sixth colorimetry converting apparatus, a switching signal generation circuit for generating switching signals corresponding to each input video signals respectively supplied to the first switch, the first converting circuit, and the second switch. The switching signals change during vertical blanking period.
The third colorimetry converting apparatus may further include a switching signal generation circuit for generating switching signals corresponding to each input video signals respectively supplied to the first switch, the first converting circuit, and the second switch. The switching signals change during a vertical blanking period.
In the sixth colorimetry converting apparatus, the switching signal generation circuit may further generate a fourth switching signal supplied to the second coverting circuit which converts the RGB-color signal to the single video signal. The switching signal changes during a vertical blanking period.